1. Field of the Invention
The present invention relates generally to motion control systems. It relates more particularly to a system for controlling the motion of an audio transport responsive to the motion of an audio input, for synchronizing media recording and playback.
2. Art Background
Signal processors have been used recently to control motion in various devices. In general there is an input that tells the system what state it should be in, such as a position, pressure, current through a motor winding, or the like. The input goes into a motion controller. There is a generalized system that is being controlled, which has an actual state, such as its present position, pressure, current, or the like. The system may include a network and a feedback loop. There can be delays introduced in the states in processing through the system. The states may be compared in a comparing element, and if they are the same, then the output from the comparing element is zero. If the states are different, there is an error between where the system is and where it should be, which needs to be addressed. Traditional motion controllers attempt to minimize the error between the present input and the present state of the system.
However, in a device such as an audio player and recorder for media playback and recording, which includes a system of networked components for processing the motion imparted by a user to an audio input to generate an audio sample rate output for controlling the motion of an audio transport, to synchronize the motion of the audio transport to the audio input, traditional motion controllers may be unstable because the system architecture introduces a significant delay between the motion controller and the transports being controlled. Also, system implementation is complicated because of the need to keep track of the delayed inputs which have not taken effect in the system, to accumulate that information, and to determine what inputs to send next to correct for the delays in addition to sending the new input.
Therefore, there has been a need existing for a system which is capable of synchronizing the motion of an audio transport for media recording to the motion of an audio input for media playback, which compensates for delays in the system between the input and the transport. The present invention fulfills those needs.